Airfoil evaporator with liquid distributor means



July 4, 1961 B. E. wElBER'r, JR

AIRFOIL. EVAPORATOR WITH LIQUID DISTRIBUTOR MEANS Filed March l0, 1960BY @www uw AGENT- United States Patent C) 2,990,700 AIRFOIL EVAPGRATORLIQUID DISTRIBUTGR MEANS Bayard E. Weibert, Jr., P.0. Box 1636,Farmington, N. Mex. Filed Mar. 1960, Ser. No. 14,076 2 Claims. (Cl.62-527) This invention relates to improvements in evaporators for aircoolers and more particularly to an improved airfoil evaporator equippedwith internal liquid refrigerant spray means.-

Air conditioning coils in common use today are designed to ydevelopmaximum heat transfer through fine fin spacing with medium temperatureranges to provide a wide range of humidity control. However, as isevident in the art of automotive air conditioning, a considerably highercooling capacity can be developed within tolerable limits of humiditycontrol by using substantially lower coil temperatures. The finehumidity control assumed necessary in most air conditioning applicationscan be dispensed Iwith in certain cooling applications in addition toautomotive air conditioning, for example, supermarkets and othershopping centers. As for the necessity of filtering the cooled air,while it does benefit to do so, there are many examples where filteringthe air is not of suficient benefit to warrant the use of filters.However, the ne fin coil must have a filter when used as a dehumidifyingmeans, otherwise the fine air passages will soon become clogged bywetted dust and lint passing through.

An important object of the present invention is to provide an evaporatorincorporating rows of airfoil shaped heat exchangers that are relativelywidely spaced apart to prevent clogging by dust and lint passingtherebetween.

Another object of the invention is the provision of an evaporator withrows of smooth normally vertically disposed airfoil shaped heatexchangers characterized by high condensate liow which washes impingedmatter down while allowing some particles to pass through and notrequire regular cleaning.

A further object is to provide an evaporator comprising rows of airfoilshaped heat exchangers suitable for operation Iat relatively lowtemperatures whereby a wide temperature difference between the exchangersurface and the passing air stream develops high cooling capacity.

Other objects and advantages of the invention will become apparentduring the course of the following detailed description taken inconnection with the accompanying drawing forming a part of thisspecification and in which drawing? IFIG. l is a fragmentary view of theairfoil evaporator partly in top plan and partly in horizontal section.

FIG. 2 is -a vertical cross sectional view of the evaporator takensubstantially on the line 2-2 of FIG. 1 and diagrammatically showing theevaporator connected in a refrigeration circuit.

VIn the drawing which, for the purpose of illustration, shows only apreferred embodiment of the invention and wherein similar referencecharacters denote corresponding parts throughout the views, the numeral10 designates a refrigeration circuit including a motor compressor 11having a discharge pipe 12 for conducting hot gas to acondenser-receiver 13 provided with an outlet pipe 14 for conductingliquid refrigerant through an expansion valve 15 to a header I16.

Referring now to the evaporator 17, this unit comprises first and secondparallel rows 18, 19 of spaced apart airfoil shaped heat exchangershaving a staggered arrangement such that the heat exchangers 20 ofeither row 18, 119 are disposed opposite spaces 21 between heatexchangers 20 of the other rows 18, 19. Upright bafes 22,

ice

2-3 at opposite ends of different rows 18, 1-9 continue the staggeredarrangement and maintain even spacing.

Each heat exchanger 20 comprises two spaced parallel'. sidewalls 24, 25and rounded marginal edge walls 2.6, 2 7 forming a hollow body 28. Theseheat exchangersV 20 are disposed between and afiixed to upper and lowerplates 29, 30 as by welding 31 so that each hollow body 2-8 is closed atboth ends and the spacing of the rows 18, 19 and the individual heatexchangers 20 is made permanent. Disposed in central longitudinalrelation in each heat exchanger body 28 is a liquid distributor tube 32having an inlet end portion 33 that extends through the upper plate 29and is fixed thereto as by welding 34. Each liquid distributor tube 32is of a length substantially equal to the length of the heat exchangers20 so that its lower end 35 terminates at the base plate 30. Each tube32 is provided with longitudinally and circumferentially spacedperforations 36 and the upper ends 33 of the tubes 32 are connected byindividual pipes 3-7 to the header 16 so that liquid refrigerant will besprayed evenly over the inside surfaces of the heat exchanger bodies 28during operation of the refrigerator system 10.

Located in the base plate 30 at the lower ends of the heat exchangerbodies '28 are ports 38 connected by outlet pipes 39 to a suction headertube 40 that returns the refrigerant to the motor compressor 11. Thisevaporator 17 lwith means for circulating air 41 through the branchedpassageways formed by the spaces 21 between the heat exchanger bodies2.8 in the two parallel rows 18, 19 is wel-l suited for use as asuspended unit cooler capable of being spotted with other units of thesame type in large areas such as in supermarkets and other shoppingcenters and without needing expensive duct work.

In the operation of the evaporator 17, the liquid refrigerant travelsdown the perforated distributor tubes 32 each in a different one of theheat exchanger bodies 28 and is sprayed through the spaced perforations36 onto the inside surfaces of the bodies 28 and leaves through theoutlet pipes 39 in the base plate 30. By using smooth airfoil shapedheat exchangers 20 at low temperature for cooling, the use of filters isavoided and high cooling capacity is developed through the use of theinserted perforated tubes 32 and the provision of the relatively largearea of the evaporator surfaces.

This construction eliminates the accumulation of liquid at the bottom ofthe hollow heat exchanger bodies 28 and resultant uneven temperatures ofthe heat exchanger surfaces.

Various changes may be made in the form of invention herein shown anddescribed without departing from the spirit of the invention and thescope of the following claims..

I claim:

1. An evaporator comprising a plurality of elongated normally verticalhollow bodies of airfoil shape in cross section, lower and upper spacedcommon end walls between which said elongated hollow bodies extend andare fixed in spaced parallel relation, said lower end wall beingprovided with uid outlets each for a different one of said hollowbodies, a plurality of liquid distributor tubes each having an inlet endportion for receiving liquid refrigerant, means fixing said tubes incentral longitudinal relation each in a different one of said elongatedhollow bodies with their inlet end portions extending `through saidupper end wall, said tubes having perforations spaced to spray liquidrefrigerant onto the inside surfaces of said hollow bodies, and headersone connected to said outlets and another to said inlet end portions.

2. An evaporator comprising adjacent parallel rows of elongated normallyvertical hollow bodies of airfoil shape in cross section, lower andupper spaced common end walls between which said elongated hollow bodiesextend and are fixed in spaced parallel relation with the bodies of eachrow in alignment with the spaces of the adjacent row, said lower endwall being provided with tluid outlets each for a different one of saidhollow bodies, a plurality of liquid distributor tubes each having aninlet end portion for receiving liquid refrigerant, means fixing saidtubes in central longitudinal relation each in a different one of saidelongated hollow bodies with their inlet end portions extending throughsaid upper end wall, said tubes having perforations spaced to sprayliquid refrigerant 10 2,508,625

onto the inside surfaces of said hollow bodies, and headers .oneconnected to said outlets and another to said inlet end portions.

References Cited in the le of this patent UNITED STATES PATENTS1,887,093 Harnett et al Nov. 8, 1932 1,952,896 Rudortf Mar. 27, 19342,327,140 Speirs Aug. 17, 1943 Smith May 23, 19501l

